The light press air dodge is so amazing that if it gets invalidated (they fix offline to be able to save replays/wifi), and it doesn't get implemented then to be turn-on-able per controller slot through some kind of option, then it's a greater downfall than any other anything ever.
It's worth noting that it takes 1 extra frame for you to be airborne in PM as compared to Melee. I'm not sure if this affects wavedashing but I know that it does give you one extra frame to shorthop (eg 3 instead of 2 on Sheik) so that could be what's making it hard for you.
it only Checks differently than Melee, all the frame data like when you're air born is the same, it just checks on the last frame possible while Melee checked to see if your button was released a frame prior than the last just to aggravate us. You're right that it could effect people's feel for stuff though.
I also don't understand how light press vs hard press matters when he's using just "Y" to be his shield and input his air dodge?